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Merge tag 'pstore-v4.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

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Pull pstore updates from Kees Cook:
 "This has a large internal refactoring along with several smaller
  fixes.

   - constify compression structures; Bhumika Goyal

   - restore powerpc dumping; Ankit Kumar

   - fix more bugs in the rarely exercises module unloading logic

   - reorganize filesystem locking to fix problems noticed by lockdep

   - refactor internal pstore APIs to make development and review
     easier:
      - improve error reporting
      - add kernel-doc structure and function comments
      - avoid insane argument passing by using a common record
        structure"

* tag 'pstore-v4.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: (23 commits)
  pstore: Solve lockdep warning by moving inode locks
  pstore: Fix flags to enable dumps on powerpc
  pstore: Remove unused vmalloc.h in pmsg
  pstore: simplify write_user_compat()
  pstore: Remove write_buf() callback
  pstore: Replace arguments for write_buf_user() API
  pstore: Replace arguments for write_buf() API
  pstore: Replace arguments for erase() API
  pstore: Do not duplicate record metadata
  pstore: Allocate records on heap instead of stack
  pstore: Pass record contents instead of copying
  pstore: Always allocate buffer for decompression
  pstore: Replace arguments for write() API
  pstore: Replace arguments for read() API
  pstore: Switch pstore_mkfile to pass record
  pstore: Move record decompression to function
  pstore: Extract common arguments into structure
  pstore: Add kernel-doc for struct pstore_info
  pstore: Improve register_pstore() error reporting
  pstore: Avoid race in module unloading
  ...
This commit is contained in:
Linus Torvalds
2017-05-02 10:35:45 -07:00
parent c58d4055c0 3a7d2fd16c
commit 2575be8ad3
11 changed files with 600 additions and 454 deletions
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156
include/linux/pstore.h
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@@ -30,7 +30,9 @@
#include <linux/time.h>
#include <linux/types.h>
/* types */
struct module;
/* pstore record types (see fs/pstore/inode.c for filename templates) */
enum pstore_type_id {
PSTORE_TYPE_DMESG = 0,
PSTORE_TYPE_MCE = 1,
@@ -45,42 +47,146 @@ enum pstore_type_id {
PSTORE_TYPE_UNKNOWN = 255
};
struct module;
struct pstore_info;
/**
* struct pstore_record - details of a pstore record entry
* @psi: pstore backend driver information
* @type: pstore record type
* @id: per-type unique identifier for record
* @time: timestamp of the record
* @buf: pointer to record contents
* @size: size of @buf
* @ecc_notice_size:
* ECC information for @buf
*
* Valid for PSTORE_TYPE_DMESG @type:
*
* @count: Oops count since boot
* @reason: kdump reason for notification
* @part: position in a multipart record
* @compressed: whether the buffer is compressed
*
*/
struct pstore_record {
struct pstore_info *psi;
enum pstore_type_id type;
u64 id;
struct timespec time;
char *buf;
ssize_t size;
ssize_t ecc_notice_size;
int count;
enum kmsg_dump_reason reason;
unsigned int part;
bool compressed;
};
/**
* struct pstore_info - backend pstore driver structure
*
* @owner: module which is repsonsible for this backend driver
* @name: name of the backend driver
*
* @buf_lock: spinlock to serialize access to @buf
* @buf: preallocated crash dump buffer
* @bufsize: size of @buf available for crash dump writes
*
* @read_mutex: serializes @open, @read, @close, and @erase callbacks
* @flags: bitfield of frontends the backend can accept writes for
* @data: backend-private pointer passed back during callbacks
*
* Callbacks:
*
* @open:
* Notify backend that pstore is starting a full read of backend
* records. Followed by one or more @read calls, and a final @close.
*
* @psi: in: pointer to the struct pstore_info for the backend
*
* Returns 0 on success, and non-zero on error.
*
* @close:
* Notify backend that pstore has finished a full read of backend
* records. Always preceded by an @open call and one or more @read
* calls.
*
* @psi: in: pointer to the struct pstore_info for the backend
*
* Returns 0 on success, and non-zero on error. (Though pstore will
* ignore the error.)
*
* @read:
* Read next available backend record. Called after a successful
* @open.
*
* @record:
* pointer to record to populate. @buf should be allocated
* by the backend and filled. At least @type and @id should
* be populated, since these are used when creating pstorefs
* file names.
*
* Returns record size on success, zero when no more records are
* available, or negative on error.
*
* @write:
* A newly generated record needs to be written to backend storage.
*
* @record:
* pointer to record metadata. When @type is PSTORE_TYPE_DMESG,
* @buf will be pointing to the preallocated @psi.buf, since
* memory allocation may be broken during an Oops. Regardless,
* @buf must be proccesed or copied before returning. The
* backend is also expected to write @id with something that
8 can help identify this record to a future @erase callback.
*
* Returns 0 on success, and non-zero on error.
*
* @write_user:
* Perform a frontend write to a backend record, using a specified
* buffer that is coming directly from userspace, instead of the
* @record @buf.
*
* @record: pointer to record metadata.
* @buf: pointer to userspace contents to write to backend
*
* Returns 0 on success, and non-zero on error.
*
* @erase:
* Delete a record from backend storage. Different backends
* identify records differently, so entire original record is
* passed back to assist in identification of what the backend
* should remove from storage.
*
* @record: pointer to record metadata.
*
* Returns 0 on success, and non-zero on error.
*
*/
struct pstore_info {
struct module *owner;
char *name;
spinlock_t buf_lock; /* serialize access to 'buf' */
spinlock_t buf_lock;
char *buf;
size_t bufsize;
struct mutex read_mutex; /* serialize open/read/close */
struct mutex read_mutex;
int flags;
void *data;
int (*open)(struct pstore_info *psi);
int (*close)(struct pstore_info *psi);
ssize_t (*read)(u64 *id, enum pstore_type_id *type,
int *count, struct timespec *time, char **buf,
bool *compressed, ssize_t *ecc_notice_size,
struct pstore_info *psi);
int (*write)(enum pstore_type_id type,
enum kmsg_dump_reason reason, u64 *id,
unsigned int part, int count, bool compressed,
size_t size, struct pstore_info *psi);
int (*write_buf)(enum pstore_type_id type,
enum kmsg_dump_reason reason, u64 *id,
unsigned int part, const char *buf, bool compressed,
size_t size, struct pstore_info *psi);
int (*write_buf_user)(enum pstore_type_id type,
enum kmsg_dump_reason reason, u64 *id,
unsigned int part, const char __user *buf,
bool compressed, size_t size, struct pstore_info *psi);
int (*erase)(enum pstore_type_id type, u64 id,
int count, struct timespec time,
struct pstore_info *psi);
void *data;
ssize_t (*read)(struct pstore_record *record);
int (*write)(struct pstore_record *record);
int (*write_user)(struct pstore_record *record,
const char __user *buf);
int (*erase)(struct pstore_record *record);
};
/* Supported frontends */
#define PSTORE_FLAGS_DMESG (1 << 0)
#define PSTORE_FLAGS_FRAGILE PSTORE_FLAGS_DMESG
#define PSTORE_FLAGS_CONSOLE (1 << 1)
#define PSTORE_FLAGS_FTRACE (1 << 2)
#define PSTORE_FLAGS_PMSG (1 << 3)